The Guam Research Center is concerned with studying etiologic factors, pathogenetic mechanisms, and therapeutic approaches to Guamanian amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia (PD). Current projects include maintenance of a tissue bank in Bethesda, virologic studies including the search for a possible C-type virus particle in Guamanian tissue, genetic studies of high incidence villages, metabolic studies including Arginine Tolerance Tests on ALS and PD patients, neuropathologic studies in Guamanian brains to characterize the neurofibrillary tangles and study of the long-term effects of L-dopa on PD patients. In the coming year immunology and virology research will be stressed, particularly HLA typing, search for C-type virus particle, tissue culture and inoculation experiments.